Best answer

I know I answered this one via email but I thought this answer would be good for anyone else in community to see as well!

We don’t label the scale automatically so as to give survey builders the option to explain the scale how they best see fit.
One of the benefits of NPS is that since it has a 0 in the scale, it’s usually clear to respondents that 10 is good and 0 is bad.

Some survey builders like to put a parenthetical like you have, while others chose to utilize the Far Left/Far Right labels that you can designate on the Layout tab of the question to put Not Likely/Very Likely on the extreme ends. Generally, I recommend using the labels on the ends but that really comes down to personal preference.

(Do note that saying 5=Neutral could potentially skew the data as it’s technically considered a Detractor when you look at the methodology for how NPS is scored)